Compass attachment



Jan. 16, 1945. G. R. HUNT COMPASS ATTACHMENT Filed Aug. 24, 1945gwua/vvtw GEOQGE QHUNT awe Patented Jan. 16, 1945 UNITED STATES PATENTOFF'I CE CQMPASS ATTACHMENT George R. Hunt, Akron, Ohio ApplicationAugust 24, 1943;. Serial NmA9fl+8fi7 9 Claims.

This invention relates to improvements, in compasses and the like usedin marking circles and arcs thereof. More particularly it relates to animproved holder for properly carrying soapstone or talc Or other markingmediums on one leg of a compass, whereby such mediums will not breakunder the pressure exerted when using the compass, and wherebyadjustments for different angles and on account of wear may be madequickly and easily.

In connection with the manufacture of many items today, for example,such as airplane jigs, steel plates, forgings, steel fabrication, andother work with sheet metal, a large amount of layout work is requiredpreliminary to cutting, and compasses are in almost constant use. Inmany plants it is preferred to use soapstone or talc as: a markingmedium on one leg of the compass, but since this marking medium issomewhat brittle it is difiicult to use it in relatively long sectionswithout breaking the section intermediate its ends when pressure isapplied while using the compass.

It is an object of this invention to provide an improved holder forsoapstone and other marking mediums whereby relatively long sectionsthereof may be adjustably carried in the holder without breaking whilethe compass is in use.

Another object is to provide for ready adjustment of the holder todifferent angles as well as for adjustment of the marking medium therebyit may be continuously extended through the lower end of the holder asthe operative end of the marking medium wears down in use.

A further object is to provide a novel holding means in the form of anelongated, relatively wide channel member having spring means extendingfor a substantial portion of said member to bear against and hold amarking medium in said member, and having a pressure link or ringsurrounding said member and said spring to yielclably hold a substantialportion of the latter against said marking medium.

A further object is to provide holding mechanism of the characterreferred to which can be quickly released from holding engagement withthe marking medium to permit removal of short stubs of the latter whichcan no longer be economically used, and to permit replacement of suchstubs with relatively long sections of marking medium.

Other objects and advantages will become apparent from the followingdescription taken in conjunction with the accompanying drawing.

In the drawing:

Fig. 1 is a frontzviews of acompass embodying my invention,

Fig; 2 is an enlarged detail View of theholder and marking medium,

Fig. 3 is an enlarged sectionalv vievw through the holder takensubstantially on line 3-3. of Fig; 4', and

Fig. 4- is top view of the holder;

Referring to the drawing thenumerals: t0 and H indicate respectively thetwo legs of acompass which. are pivotally joinedrtogether at their upperends, as indicated. at. 12,. and are-provided with a finger grippingextension I3. Below the: joint l2 an arcuate adjusting bar It is:suitably secured to the legs Ill and H; to permit the latter to be heldin any. desired spaced relation As shown, one end of bar I4: is, securedtoleg [0 as by a pint5, while leg H is movable along the bar and can besecured thereto at any dc.- sired point by tightening a thumb screw itin the usual manner. The lower end of leg; Ill carries the customaryadjustable metal point: Ft.

All of the foregoing elements are well known in the art and form no partof my invention; except in combination with the holder for the markingmedium which. will? nowbe described;

As clearly shown. in Fig. 1, leg H is made shorter than leg [0 and thelower end of the former is received in a socket member [8: in which itmay be suitably secured as by welding. Member 18 has an enlargedbifurcated annular portion l9 which pivotally receives between itsbifurcations an extension 2!) formedv on the back of a channel member2|. The-pivotal action of member I8 is obtained by means of a pin 22which extends through members l8 and 20 and has a squared portion 23:adjacent its-head which is received in a similarly shaped opening formedin one bifurcation of the annular portion [9. Thus, turning movementofthe member It also turns the pin 22 and a wing nut 24 is arranged on pin22 to tighten the pivotal joint. and hold channel member 21 at any:desired. angle with respect'to' member l 8..

The channel member 2t is relatively wide, having its sides 25 formedwith rounded extensions 26, and from the latter these sides' taperdownwardly as indicated at 21. A marking medium 28 is received inchannel member M and rests against acorrugated surface 29 (-Fig. 2)formed on the latter, which surface is adapted to prevent slippage ofthe marking medium. This marking medium is preferably soapstone or talc,but may be ofany' other suitable. materrial". As; will be noted, the:marking medium... is

preferably fiat and also relatively wide so as to be received in thechannel member 2| without too much p ay between the sides 25. Themarking medium is also of substantial length when it is first insertedin the channel member, being preferably longer than the latter so as toextend beyond the channel member at both ends thereof. The lower end ofthe marking medium is sharpened as indicated at 29 so that a clear, sharline will be made.

In the extensions 26, the free ends 30 of an elongated wire spring 3|are inserted, and the loop 32 of this spring extends almost to the lowerend of the member 2| to bear against the lower portion of the markingmedium. As clearly shown in Figs. 1 and 3, the legs of spring 3| areslightly curved inwardly toward the marking medium whereby a portion ofthese legs as well as the looped end of the spring will bear against themarking medium, thus permitting a greater area of the spring to engagethe marking medium than would be possible if this curve were omitted.

This arrangement is less likely to cause breakage of a brittle markingmedium since the pressure of the spring is applied over a substantialarea.

The lower end of the channel member receives a pressure link or ring 33which extends over the legs of spring 3| and by virtue of the taperedsides on member 2| can be forced upwardly on member 2!, as shown in fulllines in Fig. 3, to securely hold the spring in engagement with themarking medium. To prevent the link 33 from slipping oil the lower endof the channel member, a portion 34 of the latter is bent reairwardly soas to prevent downward movement of the link, as indicated in Fig. 3. Itwill be apparent that marking mediums of various thicknesses may beutilized in this holder because the link 33 can be moved to the desiredposition to insure proper engagement of the spring with the markingmedium.

In using this holder initially the link 33 is moved to its lowestposition and a section of marking medium is quickly and easily insertedinto the channel member 2| from the top thereof until the lower endextends outwardly to the desired position. The marking medium willfreely pass between the spring 3| and the corrugated surface on thechannel member as long as the link 33 is in its lowest position. Whenthe marking medi um is properly placed the link 33 is moved upwardly toforce the spring into holding engagement with the marking medium, andthe link will frictionally hold its position until it is again moveddownwardly.

As the lower end of the marking medium wears down in use, the link 33may be quickly moved downwardly sufiiciently to permit the markingmedium to be further extended at the lower end of the channel member,after which the link may be quickly moved upwardly again to its properholding position. Since the spring 3| engages the marking medium nearthe lower end of the latter, all of the marking medium except a shortstub may be used up before it is necessary to insert a new section ofsuch medium. However, when it does become necessary to insert a newsection, the stub of the old section can be quickly released at thebottom of the channel member and the new section moved into place.

While I have illustrated and described one form of my invention it willbe obvious that the invention is not limited thereto, and that changesand modifications may be made therein without departing from the spiritof the invention or from the scope of the subjoined claims.

What is claimed is:

1. In a holder for a marking medium of the character described anelongated channel member in which said marking medium is received. anelongated spring member carried by said channel member and adapted tobear against said marking medium to hold the latter in said channelmember, and a pressure link surrounding said channel member and saidspring to yieldably hold said marking medium between said channel memberand said spring.

2. In a holder for a marking medium of the character described anelongated channel member, the sides of which have extensions near thetop of said member and taper downwardly toward the bottom of saidmember, said channel member being adapted to receive said markingmedium, an elongated wire spring having its upper ends received in saidextensions and its lower end adapted to engage said marking medium, anda pressure link surrounding said channel member and said spring andmovable on the tapered sides of said channel member to yieldably holdsaid marking medium between said channel member and said spring.

3. A device of the character defined in claim 1 wherein the surface ofsaid channel member in engagement with said marking medium is corrugatedto prevent slipping of said medium.

4. A device of the character defined in claim 1 wherein said spring iscurved inwardly toward said marking medium to insure that more than themere end of the spring will be in engagement with the marking medium.

5. A device of the character defined in claim 1 wherein said channelmember has a portion bent outwardly to prevent said link from becomingcompletely disengaged from the channel member.

6. A holder for a marking medium of the character described comprising achannel member having a corrugated surface against which said markingmedium is adapted to bear, a spring carried by said channel member andadapted to engage said marking medium to urge the same toward saidsurface, and a pressure link surrounding said channel member and saidspring to yieldably hold said spring in engagement with said markingmedium.

7. A holder for a marking medium of the character described comprising achannel member having a corrugated surface and downwardly tapering sideswhich are provided with extensions adjacent their upper ends, saidmarking medium being adapted to be received between said sides andagainst said corrugated surface, a wire spring having its upper endsreceived in said extensions and its lower end adapted to bear againstsaid marking medium, and a pressure link surrounding said channel memberand said spring and movable on the tapered sides of said channel memberto yieldably hold said marking medium between said channel member andsaid spring.

8. A holder constructed in accordance with claim 7 wherein said springis curved inwardly toward said marking medium to insure that more thanthe mere end of the spring will be in engagement with the markingmedium.

9. A holder constructed in accordance with claim 7 wherein said channelmember has a portion bent outwardly to prevent said link from

